The present invention relates to a V-belt type transmission to be used with a continuously variable transmission for a vehicle or the like and, more particularly, to a V-belt transmission in which a number of V-shaped metal members having outward contact surfaces to contact with an endless metal belt are arranged on the metal belt serially in the longitudinal direction of the metal belt thereby to construct a V-belt as a whole so that the V-belt is made to run under tension between V-pulleys at drive and driven sides to effect the power transmission.
The V-belt transmission to be used in a continuously variable transmission is suitable for transmitting a large power because it provides relatively high frictional force. On the contrary, the V-belt has a defect that its size is enlarged if it is made of rubber.
In order to eliminate this disadvantage, the V-belt transmission made of metal has been developed.
The aforementioned V-shaped metal members have outward contact surfaces to come into abutment against the endless metal belt and arranged in a predetermined number along the whole length of the endless metal belt so that they are forced into contact with one another to apply a tension and a suitable fastening force to the metal belt.
In the Japanese Patent Application No. 58-70920, a V-belt transmission of the above type has been proposed, in which each of roller members is disposed inside of the metal belt and sandwiched between each adjoining two of V-shaped metal members. Each of the metal members has both sides, in longitudinal direction of the metal belt, formed with arcuate recess for receiving the roller member. Each of the arcuate surfaces has a radius of curvature larger than the radius of the roller members so that the wedge effect for pressing the roller members in the longitudinal direction of the metal belt may be exhibited in accordance with the successive engagement of the metal members with the V-shaped groove of a V-pulley. As a result, the gaps between the neighboring two of the metal members is enlarged through the sandwiched one of the roller members to establish a pressure as a whole in the direction to increase of radius of revolution locus of the metal members thereby to strengthen the pressure at the outward contact surfaces of each of the metal members onto the metal belt. According to this proposal, however, in order to exert a tension upon the metal belt accompanying the revolutions of the pulleys and to ensure the power transmission efficiently with smooth revolutions, it is required to bring consecutively and smoothly the metal members into engagement with the V-grooves of the pulleys and to make uniform engaging positions with respect to every metal member.
With respect to another aspect of the conventional V-belt of this type, the size of the whole length of the belt is adjusted by the V-shaped metal members. However, these V-shaped metal members are difficult to provide an accurate thickness, because they are specially shaped into a plate, so that it is troublesome to adjust the size of the total length of the belt.
According to the V-belt of this type, a metal V-belt is assembled by first assembling a predetermined total number of V-shaped metal members consecutively or simultaneously onto a metal belt and by consecutively or simultaneously pressfitting rollers or the like as the intermediate members between the adjacent two of the V-shaped metal members thereby to apply a proper fastening force to the metal belt. However, since the V-shaped metal members do not have uniform thickness with one another, and since all the metal belts do not have an equal internal diameter, it is necessary to further adjust the fastening force of the resultant metal belt.